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Which of these sets of lengths can NOT be the sides of a triangle?

Competition practiceGeometry
  • A3 cm, 4 cm, 8 cm
  • B5 cm, 6 cm, 10 cm
  • C7 cm, 7 cm, 13 cm
  • D4 cm, 9 cm, 12 cm

Step-by-Step Solution

The sum of any two sides must exceed the third. Here 3 + 4 = 7 is less than 8, so no triangle is possible. The other sets pass (11 > 10, 14 > 13, 13 > 12).
Answer: A) 3 cm, 4 cm, 8 cm

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